1,3 butylene glycol of high purity and method for producing the same

ABSTRACT

High purity 1,3-butylene glycol obtained from acetaldol by a liquid phase hydrogen reduction method, by adding a base to crude 1,3-butylene glycol free of high-boiling material, heat-treating the mixture and then distilling off 1,3-butylene glycol; and distilling off low-boiling materials from 1,3-butylene glycol. In high performance liquid chromatography analysis under specified conditions, each peak eluted in a relative retention time range of 4.0 to 5.5, taking a relative retention time of 1,3-butylene as 1.0, has an absorbance of 0.02 or less at a measuring wavelength of 210 nm. This has no odor and shows less change with time.

This is the National Phase Application of PCT/JP99/04275, filed Aug. 6,1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to high purity 1,3-butylene glycol and toproduction method thereof. More particularly, it relates to high purity1,3-butylene glycol which a small content of impurities eluted for aspecified relative retention time range in HPLC (high performance liquidchromatography) analysis under specified conditions and hence is free ofodors and has less change with time and to a method for producing highpurity 1,3-butylene glycol by adding a base to crude 1,3-butylene glycolor low quality product, heat treating and distilling.

2. Description of Related Art

1,3-Butylene glycol is a viscous, colorless and transparent, odorlessliquid that has a boiling point of 208° C. and shows excellentsolubility and produces derivatives having excellent chemical stability.

It finds use as a raw material for various synthetic resins, surfactantsand also is used as a material for cosmetics, hygroscopic agents,high-boiling solvents, anti-freezes, etc., making the best of itsexcellent hygroscopicity, low volatility, and low toxicity. Inparticular, recently, needs for non-toxic, non-irritating 1,3-butyleneglycol have been increasing in the field of cosmetics industry since ithas excellent properties as a humectant, and odorless butylene glycol isuseful as a cosmetic grade.

However, 1,3-butylene glycol obtained by the conventional methods causeschanges with time during storage in a tank to generate a slight odor sothat it is difficult to store it for a long time.

Therefore, it has been desired to provide 1, 3-butylene glycol free ofslight odor after a long-term storage.

JP-A-7-258129 discloses as a method for increasing the yield of odorlessproduct, a method in which at least one compound selected from sodiumhydroxide, potassium hydroxide, sodium hydrogen borohydride andpotassium borohydride upon distillation for removing high-boilingmaterials. However, the odorless 1,3-butylene glycol obtained by thismethod has the problem that it still generates a slight odor due tochanges with time after a long-term storage.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide high purity1,3-butylene glycol having no odor and showing less changes with timeand a production method therefor.

The present inventors have made intensive study with view to solving theproblem described in JP-A-7-258129 and as a result it has been foundthat when distillation is performed by adding an alkali metal to acharge stock solution into a de-high-boiling distillation tower, thecharge stock solution in the de-high-boiling distillation tower containsa large amount of high-boiling materials and hence the added alkalimetal base causes reaction decreasing low-boiling materials andsimultaneously generation of low-boiling materials due to decompositionreaction of high-boiling materials. As a result, odor-causing materialscan be decreased only to a certain level so that after a long-termstorage there occurs a change with time to generate a slight odor.

Accordingly, the present inventors have made further investigation andhave found that in a process for distilling and purifying 1,3-butyleneglycol, odor-causing materials can be effectively decreased by adding analkali metal base to crude 1,3-butylene glycol from which high-boilingmaterials have been removed in advance, heat-treating, distilling off1,3-butylene glycol to separate the alkali metal base and high-boilingmaterials as residues, and then distilling off a low-boiling materialform the 1,3-butylene glycol fraction. The present invention has beenaccomplished based on this finding.

Further, the present inventors have found that in HPLC (high performanceliquid chromatography) analysis, 1,3-butylene glycol having anabsorbance at a specified wavelength of a peak eluted in a specifiedrelative retention time range is odorless and shows less change withtime, thus accomplishing the present invention.

That is, the present invention provides the following:

(1) 1,3-Butylene glycol wherein in high performance liquidchromatography analysis under specified conditions, each peak eluted ina relative retention time range of 4.0 to 5.5, taking a relativeretention time of 1,3-butylene as 1.0, has an absorbance of 0.02 or lessat a measuring wavelength of 210 nm.

(2) 1,3-Butylene glycol as described in (1) above, wherein the1,3-butylene glycol is produced from acetaldol by a liquid phasehydrogen reduction method.

(3) A method for producing 1,3-butylene glycol, comprising the steps of:adding a base to crude 1,3-butylene glycol free of high-boilingmaterial, heat-treating the mixture and then distilling off 1,3-butyleneglycol; and distilling off low-boiling materials from 1,3-butyleneglycol.

(4) The method for producing 1,3-butylene glycol as described in (3)above, wherein the 1,3-butylene glycol is produced from acetaldol by aliquid phase hydrogen reduction method.

(5) The method for producing 1,3-butylene glycol as described in (4)above, wherein the crude 1,3-butylene glycol free of high-boilingmaterial is obtained from reaction product obtained from acetaldol by aliquid phase hydrogen reduction method and is distilled from ade-high-boiling material distillation tower after removal of alcohols,of water, and of salts and high-boiling materials.

(6) The method for producing 1,3-butylene glycol as described (3),wherein the base is sodium hydroxide, potassium hydroxide, or a mixturethereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of flow sheet for practicing a method for producing1,3-butylene glycol according to the present invention;

FIG. 2 is a chart of HPLC analysis of 1,3-butylene glycol relative toExamples and Comparative Examples, with FIGS. 2A, 2B, and 2C relating toExample 1, Example 2, and Comparative Example 1, respectively.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be explained.1,3-Butylene glycol according to the present invention is preferably oneproduced from acetaldol by a liquid phase hydrogen reduction method.However, it may be one produced from 1,3-butylene oxide by a hydrolysismethod or mixtures of these or any 1,3-glycol may be used.

In the liquid phase hydrogen reduction method for acetaldol, low-boilingcompounds having unsaturated bonds such as acetaldehyde, butyraldehyde,crotonaldehyde, acetone, methyl vinyl ketone, etc., which are consideredto be odor-causing materials, or condensates of these are by-produced.These are difficult to remove completely even by distillation.Therefore, in the conventional purification methods, minute amounts ofsuch odor-causing materials tend to mix in the resulting 1,3-butyleneglycol. The above odor-causing material means those that are source ofodor themselves or become odor materials by changes with time.

The conventional purification method is a method in which the reactionmixture of 1,3-butylene glycol produced by liquid phase hydrogenreduction of acetaldol is subjected to removal of alcohols, removal ofwater, removal of salts and high-boiling materials and removal ofhigh-boiling materials, then in the low-boiling material removaldistillation tower (product distillation tower) low-boiling materialsare distilled off from the top of the tower and 1,3-butylene glycol isobtained as a product from the tower bottom.

The present invention has the feature that addition of a base to crude1,3-butylene glycol having a low content of high-boiling materials andheat-treating the mixture effectively decreases odor-causing materialsand gives rise to 1, 3-butylene glycol having no odor and shows lesschange with time.

In the present invention, the crude 1,3-butylene glycol fed to thepurification step is crude 1,3-butylene glycol of which high-boilingmaterials have been removed, for example, crude 1,3-butylene glycol (CR)after the de-high-boiling material distillation described later on,1,3-butylene glycol obtained from the product distillation tower in theabove-mentioned conventional purification process, low quality product1,3-butylene glycol, product 1,3-butylene glycol of unknown origin, ormixtures of these and preferably crude ,3-butylene glycol (CR) after thede-high-boiling material distillation.

Crude 1,3-butylene glycol as just obtained by hydrogenation of acetaldolhas a high-boiling material content of usually 3 to 7%. In contrast, thecrude 1,3-butylene glycol after the removal of high-boiling materialsaccording to the invention has a high-boiling materials content of1.0%by weight or less, preferably 0.5% by weight or less.

Use of crude 1,3-butylene glycol having a low high-boiling materialcontent generates no or minimized amounts of low-boiling materials dueto decomposition reaction of high-boiling materials when heat-treatedtogether with a base, so that the low-boiling materials causing odor canbe preferentially decreased due to the reaction with alkali.

As a result, since the absolute amounts of low-boiling materials can bedecreased infinitely close to 0, it is possible to produce 1,3-butyleneglycol of very high quality, having no odor and showing less change withtime.

The low-boiling materials causing odor are considered to be those havingunsaturated bonds such as aldehydes and ketones and hence it isconsidered that addition of a base to crude 1,3-butylene glycol andheat-treating converts impurities to high-boiling materials or causesthem to be subject to reduction with hydrogen (hereafter, simplyreferred to reduction) to form alcohols, so that the absolute amount ofimpurities is decreased.

FIG. 1 is a flow sheet for an apparatus for use in an embodimentobtaining high purity 1,3-butylene glycol of the present invention,illustrating the situation of charging a base from the portion indicatein broken line.

Reference numeral 1-1 designates a dehydration tower, 1-2 designates adesalting tower (thin film evaporator), 1-3 designates a de-high-boilingmaterial distillation tower, 1-4 designates an alkali reactor, 1-5designates a dealkalization tower (thin film evaporator), 1-6 designatesa product distilling tower. 1-1-1, 1-3-1, and 1-6-1 designate reboilers,respectively, and 1-1-2, 1-2-2, 1-3-2, 1-5-2, and 1-6-2 designatecondensers, respectively.

A stands for crude 1, 3-butylene glycol liquid after the liquid phasehydrogen reduction treatment of acetaldol and dealcoholation, B standsfor discharged water, C stands for salt and high-boiling materials, Dstands for high-boiling materials, CR stands for crude 1,3-butyleneglycol after the de-high-boiling material distillation, E stands for abase, F stands for a base and high-boiling material, G stands for alow-boiling material, HP stands for high purity 1,3-butylene glycol.

Crude 1,3-butylene glycol distilled by the de-high-boiling materialdistillation tower 1-3 is fed to the alkali reactor (for example, acirculating tube type reactor) 1-4. At the same time, a base is added inan amount of 0.05 to 10% by weight, preferably 0.1 to 1.0% by weight,based on the crude 1,3-butylele glycol (CR). If the addition amount ofthe base is above 10% by weight, the base precipitates in thedistillation tower, piping, etc. to cause clogging thereof while theaddition amount is too large, contrariwise, decomposition reaction ofhigh-boiling compounds occurs to generate odor-causing materials. On thecontrary, with less than 0.05% by weight, the effect to the odor-causingmaterial is less. Thus, the both are undesirable. 1,3-butylene glycol isfed to the alkali reactor 1-4.

In the method for producing 1,3-butylene glycol according to the presentinvention, the base to be added is preferably an alkali metal compound,more preferably sodium hydroxide, potassium hydroxide, sodium(bi)carbonate, most preferably sodium hydroxide, potassium hydroxide ormixtures thereof. The base may be added in the form of solids as it is,but it is preferred to add as an aqueous solution for ease of operationand for promoting contact with the target solution.

Suitable reaction temperature in the alkali reactor 1-4 is 90 to 140°C., preferably 110 to 130° C. This is because, if the reactiontemperature is lower, a longer reaction retention time is necessary,which requires a larger volume reactor and is uneconomical. If thereaction temperature is too high, the odor of 1,3-butylene glycolincreases. The reaction retention time is 5 to 120 minutes, preferably10 to 30 minutes. If the retention time is shorter, the reaction isinsufficient, thus deteriorating the quality of final product. If theretention time is longer, a larger reactor is necessary, which increasesappliance costs and is disadvantageous economically.

The crude 1,3-butylene glycol to be charged in the alkali reactor may beany crude 1, 3-butylene glycol so far as high-boiling materials havebeen removed therefrom as described above. For example, it may be thosedistilled off from high-boiling material distillation tower or thoseproduct 1,3-butylene glycol obtained from the tower bottom of theproduct distillation tower of the above conventional method.

After discharged from the alkali reactor, the crude reaction mixture istreated in the step where 1,3-butylene glycol is distilled off to givethe base and high-boiling materials as residues and the step wherelow-boiling materials are distilled off from 1,3-butylene glycol.

Preferably, the crude reaction mixture is fed first to thedealkalization tower 1-5 (thin film evaporator) where the base used inthe reaction and the resulting high-boiling materials are removed fromthe tower bottom. The evaporator used as a dealkalization tower is anatural flow-down type thin film evaporator and forced stirring typethin film evaporator whose retention time is short are suitable forsuppressing thermal hysteresis to the process fluid.

In the evaporator, evaporation is carried out at a reduced pressure of100 torr or less, preferably 5 to 20 torr, at the top of the tower. Forthe odor of 1,3-butylene glycol, it is preferred to lower distillation(evaporation) temperature and the lower the pressure is, the moresuitable. Conducting distillation under the above conditions maintainsthe temperature of evaporator to 90 to 120° C. From the top of thetower, 1,3-butylene glycol containing low-boiling materials is distilledoff and is charged to the next product distillation tower.

The product distillation tower may be a porous plate tower, a foamedbell tower, etc. Preferably, it is a filled tower having a low pressureloss, filled with Sulzer Packing, Melapack (both are trade names forproducts by Sumitomo Heavy Industries, Ltd.), etc. is more suitable.This is because 1,3-butylene glycol is thermally decomposed at 200° C.or higher to affect adversely on odor (JP-A-63-156738) so thatdistillation temperature is to be lowered as low as possible. Whenthermal hysteresis (retention time) to 1,3-butylene glycol is long,similarly influenced. Therefore, the reboiler to be adopted is suitablya thin film evaporator, such as a natural flow-down type thin filmevaporator or a forced stirring type thin film evaporator.

The product distillation may depend on the concentration of low-boilingmaterial in the charge stock solution, but when the concentration oflow-boiling material in the charge stock solution is 5% or less, it maybe one having a theoretical number of daylights of about 10 to 20(trays). It is preferred that the charge stock solution is fed at aposition from the top of the tower to a height 20 to 70% of the heightof the tower. At this time, distillation is performed under reducedpressure of 100 torr or less, preferably 5 to 20 torr, at the top of thetower. For the odor of 1,3-butylene glycol, it is preferred to lowerdistillation temperature. The lower the pressure is, the more suitable.It is desirable to run distillation at a reflux ratio of 0.5 to 2.0.

The charging into the product distillation tower is carried out byfeeding the liquid obtained by concentrating the top of the tower vaporof the dealkalization tower in the condenser 1-5-2. Of course, todecrease the calorie for heating the product distillation tower, the topof the tower vapor from the dealkalization tower may be directly fed tothe production tower. 1,3-Butylene glycol product can be obtained fromthe tower bottom of the product distillation tower.

In the present invention, 1, 3-butylene glycol may be obtained also asfollows. That is, the treated liquid from the alkali reactor is fedfirst to the low-boiling material removal distillation tower wherelow-boiling materials are distilled off, subsequently 1,3-butlene glycolextracted from the gas phase portion in the recover trays or from thetower bottom is distilled or evaporated to remove the base and theresulting high-boiling materials as distillation residues and1,3-butylene glycol is recovered from the top of the tower or in themidway of concentration trays.

The distillate of the above low-boiling materials may further be fed toan additional distillation tower where 1 ,3-butylene glycol is distilledoff to remove high-boiling materials. Also, a portion of the1,3-butylene glycol after removal of the above low-boiling materials maybe recycled to the dealkalization tower. Alternatively, low-boilingmaterials containing 1,3-butylene glycol may be recycled to the alkalireactor.

FIG. 2 is a chart of HPLC analysis (measurement wavelength: 210 nm) of1,3-butylene glycol under specified conditions (which will be describedin detail in the column of examples). FIG. 2A is a chart whichillustrates the product of Example 1, FIG. 2B is a chart whichillustrates the product of Example 2, and FIG. 2C is a chart whichillustrates the product of Comparative Example 1. The horizontal axisrepresents elution time (where a peak exists, its retention time isindicated in minute), the vertical axis represents milli abosorbance(mAbs).

1,3-Butylene glycol has substantially no absorbance in ultravioletregions, the peak is very small and its retention time is near 5.5minutes in FIG. 2A, near 5.4 minutes in FIG. 2B, and near 5.4 minutes inFIG. 2C.

The impurities treated in the present invention have retention time of20 to 30 minutes and products of low grades have large peaks appear near23.5 minutes, 25.4 minutes, 26.4 minutes, 27.7 minutes, as shown in FIG.2C, that is, they have high absorbances. On the other hand, in the caseproducts are of relatively good quality, only small peaks (absorbance0.005 or less) will appear near 23.4 minutes and 26.3 minutes as shownin FIG. 2B. In the case products are of very high quality, no peak willappear in the range of 20 to 30 minutes (absorbance 0.005 or less).

Also, it reveals that the peak near 38 to 42 minutes gives substantiallyno influence on the odor and change with time.

That is, it reveals that various peaks eluted in a relative retentiontime in the range of 4.0 to 5.5 taking the relative retention time of1,3-butylene glycol as 1.0, have an absorbance at 210 nm of 0.02 orless, preferably 0.01 or less, the problems of odor and change with timecan be solved.

The high purity 1,3-butylene glycol obtained by the above productionmethod in the above HPLC analysis showed an absorbance at 210 nm of 0.02or less for each peak eluted in a relative retention time in the rangeof 4.0 to 5.5, having no odor and less change with time.

EXAMPLES

Hereafter, the present invention will be explained concretely in moredetail. However, the present invention is not limited thereto.

All “parts” used in examples and comparative examples are by weightunless otherwise indicated specifically.

Evaluation of 1,3-butylene glycol was made as follows.

1. Odor evaluation:

As evaluation samples, 1,3-Butylene glycol of which no odor was felt wasassigned 1, 1,3-butylene glycol substantially odorless was assigned 5,and 1,3-butylene glycol of which slight odor was felt was assigned 10,and scores were obtained by relative evaluation. The evaluation sampleswere each mixed with water in a ratio of 1:1, and charged in a jar witha ground-in stopper. This was sealed and left to stand at roomtemperature. Then the odor was smelled quickly in the air, and comparedand scored.

2. Test on change with time:

The sample charged in a jar with a ground-in stopper, the gas portionwas nitrogen-sealed. Thereafter, the sealed sample was stored in anincubator kept at 40° C. for 3 months and then subjected to HPLCanalysis and odor evaluation.

3. Ultraviolet spectroscopic (UV) analysis:

Analyzer: Shimadzu Spectrophotometer UV-12000

Cell width (light path length): 10 mm

Solution in reference cell: Distilled water

Sample: A solution of product 1,3-butylene glycol diluted in distilledwater to 10 vol%

Measurement: Absorbance at a measuring wavelength of 210 nm wasmeasured.

4. HPLC analysis:

Analyzer: Shimadzu LC6A

Detector: SPD-M10A (light path length of cell 10 m)

Detection wavelength: 210 nm Analysis column: ODS column YMCpackA-312(φ: 4.6 mm×120 mm) two columns

Analysis condition: Column temperature 40° C.

Moving phase: Acetonitrile/0.2% H₃PO₄ aqueous solution=20/80 (vol ratio)

Flow rate of moving phase: 1.2 ml/min.

Sample injection amount: 25 μl of 10 w/v % 1,3-butylene glycol movingphase solution

Absorbance at a measuring wavelength of 210 nm of each peak eluted in arelative retention time in the range of 4.0 to 5.5 taking the relativeretention time of 1,3-butylene glycol as 1.0 was measured.

EXAMPLE 1

A method of the present invention is explained based on examples inaccordance with a flow sheet shown in FIG. 1. 100 parts of acetaldol and6.5 parts of hydrogen were charged into a liquid phase hydrogenreduction reactor (not shown) as materials. Then, Raney nickel was addedthereto as a catalyst, and the reactor was maintained at a temperatureof 125 to 135° C. and a pressure of 150 kg/cm², and liquid phasehydrogen reduction was conducted. After the reaction, the catalyst wasremoved from the liquid and the liquid was neutralized with sodiumhydroxide. Removal of alcohols therefrom afforded crude 1,3-butyleneglycol (A).

The crude 1,3-butylene glycol (A) was charged into dehydration tower 1-1shown in FIG. 1. In the dehydration tower, water was released from thetop of the tower, and 15 parts of fresh water per 100 parts of chargedliquid volume was added as a reflux to obtain crude 1,3-butylene glycolcontaining 0.5% by weight or less of water at a pressure of 50 torr fromthe bottom of a distillation tower.

Then, dehydrated crude 1,3-butylene glycol was charged intoademineralization tower 1-2. Here, 5 parts per 100 parts of chargedliquid volume of a part of salts, high-boiling point materials, and the1,3-butylene glycol were discharged from the bottom. 95 parts per 100parts of charged liquid volume of a part of the 1,3-butylene glycol andlow/high boiling point materials were distillated.

A part of the 1,3-butylene glycol and low/high boiling point materials,which were distillated from the demineralization tower 1-2, were chargedinto a high-boiling point materials removal distillation tower 1-3, 20parts of a part of high boiling point materials and the 1,3-butyleneglycol were discharged from the bottom. 80 parts of the crude1,3-butylene glycol (CR) containing low boiling materials was distilledfrom the top of the tower and the glycol was charged into an alkalireactor 1-4. In this time, 10% by weight of sodium hydroxide solutionwas added so as to be 0.2% by weight of sodium hydroxide to the chargedliquid. The reaction was conducted for a retention time of 20 and thetemperature in the alkali reactor was maintained at 120° C.

A crude reaction liquid, which flew out of the reactor, was charged intoa dealkalization tower. In this case, 10 parts per 100 parts of thecharged liquid of a part of sodium hydroxide, high-boiling pointmaterials, and 1,3-butylene glycol were discharged. 90 parts per 100parts of the charged liquid of 1,3-butylene glycol and low boiling pointmaterials were distilled from the top of the tower, and charged into thenext production tower. In a production distillation tower 1-6, 10% byweight per 100 parts of a charged liquid of a part of low boilingmaterials and 1,3-butylene glycol were distilled from the top of thetower, product 1,3-butylene glycol was extracted from the bottom of thetower.

1,3-butylene glycol of immediately after production had 3 of odor marksand 0.001 of an absorbance at 210 nm by an ultraviolet spectrophotometerunder the prescribed conditions. And the glycol had 0.005 or less of theabsorbance of each peak which eluted in the range of 4.0 to 5.5 forrelative retention time in the HPLC analysis.

A test for change with time using this 1,3-butylene glycol was conductedat 40° C. The odor marks was 3 and the absorbance at 210 nm by anultraviolet spectrophotometer under the prescribed conditions was 0.001after 1 month. According to this result, no change was observed.

3 Month later, the absorbance at 210 nm by an ultravioletspectrophotometer under the prescribed conditions was 0.002 which waslittle increased, and the amount of minute impurities was increased tosome extent. However, the absorbance of each peak which eluted in therange of 4.0 to 5.5 for relative retention time in the HPLC analysis was0.005 or less, and the odor marks was 3 and still odorless. The resultwas shown in Table 1.

EXAMPLE 2

1,3-Butylene glycol was produced in the same manner as the reaction inExample 1 except that the reaction was conducted at a temperature of100° C. and a retention time of 30 minutes.

Comparative Example 1

The process was run in the same manner as in Example 1 up to the step ofthe high-boiling materials removal distillation tower 1-3. 1,3-Butyleneglycol and low boiling point materials were distillated from the top ofthe high-boiling materials removal distillation tower 1-3. Thedistillated liquid was charged into the production tower as it is. Inthe production tower 1-6, 10% by weight per 100 parts of the chargedliquid of a part of low boiling materials and 1,3-butylene glycol weredistillated from the top of the tower. Product 1,3-butylene glycol wasextracted from the bottom of the tower.

1,3-Butylene glycol of immediately after production had 3 of odor marksand 1.131 of an absorbance at 210 nm by an ultraviolet spectrophotometerunder the prescribed conditions. The glycol had 0.005 or more of theabsorbance of each peak which eluted in the range of 4.0 to 5.5 forrelative retention time in the HPLC analysis.

A test for change with time using this 1,3-butylene glycol was conductedat 40° C. The odor marks was 5 and the absorbance at 210 nm by anultraviolet spectrophotometer under the prescribed conditions was 1.160after 1 month. According to this result, no change was observed. 3 Monthlater, the odor marks was 10 and the absorbance at 210 nm by anultraviolet spectrophotometer under the prescribed conditions was 1.193.The absorbance of each peak which elute in range of 4.0 to 5.5 forrelated retaining time in the HPLC analysis was 0.005 or more and asmall quantity of odor was occurred. The result was shown in Table 1.

Comparative Example 2

Sodium hydroxide was added when conducting distillation of high-boilingmaterials in accordance with the method described in JP-A No. 7-258129.The process was run in the same manner as in Example 1 up to the step ofthe demineralization tower 1-2. A part of 1,3-butylene glycol andlow/high boiling point materials which were distillated from the top ofthe demineralization tower 1-2 were charged into the distillation ofhigh-boiling point materials tower 1-3. In this time, 10% by weight ofsodium hydroxide solution was added so as to be 0.5% by weight of sodiumhydroxide to the charged liquid. In the high-boiling materials removaldistillation tower, 20 parts of high boiling materials, sodiumhydroxide, and 1,3-butylene glycol was discharged from the bottom. 80parts of the 1, 3-butylene glycol containing low boiling materials wasdischarged from the top of the tower and the glycol was charged into anext production tower.

In the production tower 1-6, 10% by weight per 100 parts of the chargedliquid of a part of low boiling point materials and 1,3-butylene glycolwere distillated from the top of the tower and product 1,3-butyleneglycol was extracted from the bottom of the tower.

1,3-Butylene glycol of immediately after production had 3 of odor marksand 0.793 of an absorbance at 210 nm by an ultraviolet spectrophotometerunder the prescribed conditions. And some glycol had 0.05 or more of theabsorbance of each peak which eluted in the range of 4.0 to 5.5 forrelative retention time in the HPLC analysis.

A test for change with time using this 1,3-butylene glycol was conductedat 40° C. The odor marks was 4 and the absorbance at 210 nm by anultraviolet spectrophotometer under prescribed conditionwas 0.847 after1 month. And 3 month later, the odor marks was 7 and the absorbance at210 nm by an ultraviolet spectrophotometer under prescribed conditionwas 0.928. Some absorbance of peak which eluted in range of 4.0 to 5.5for relative retention time in the HPLC analysis was 0.05 or more and aslight odor occurred.

TABLE 1 HPLC Odor UV absorbance absorbance After After After After AfterJust 1 3 Just 1 3 Just 3 after month month after month month after monthExample 3 3 3 0.001 0.001 0.002 0.005 0.005 1 or or less less Example 3— 3 — — — 0.01 0.01 2 or or less less Compara- 3 5 10 1.131 1.160 1.1930.05 0.05 tive or or Example more more 1 Compara- 3 4 7 0.793 0.8470.928 0.05 0.05 tive or or Example more more 2

According to the present invention, a high quality of 1,3-butyleneglycol, which is non-odor and little changing with time is provided. Andthe glycol can be used for a synthetic resin, a surfactant, ahygroscopic agent, a high-boiling solvent, an anti-freeze, in particulartoiletry materials making the best of hygroscopicity, low-volatility,and low-toxicity.

What is claimed is:
 1. 1,3-Butylene glycol wherein in high performanceliquid chromatography analysis under specified conditions, each peakeluted in a relative retention time range of 4.0 to 5.5, taking arelative retention time of 1,3-butylene as 1.0, has an absorbance of0.02 or less at a measuring wavelength of 210 nm.
 2. 1,3-Butylene glycolas claimed in claim 1, wherein the 1,3-butylene glycol is produced fromacetaldol by a liquid phase hydrogen reduction method.
 3. A method forproducing 1,3-butylene glycol, comprising the steps of: adding a base tocrude 1,3-butylene glycol free of high-boiling material, heat-treatingthe mixture and then distilling off 1,3-butylene glycol; and distillingoff low-boiling materials from 1,3-butylene glycol.
 4. The method forproducing 1,3-butylene glycol as claimed in claim 3, wherein the 1,3-butylene glycol is produced from acetaldol by a liquid phase hydrogenreduction method.
 5. The method for producing 1,3-butylene glycol asclaimed in claim 4, wherein the crude 1,3-butylene glycol free ofhigh-boiling material is obtained from reaction product obtained fromacetaldol by a liquid phase hydrogen reduction method and is distilledfrom a de-high-boiling material distillation tower after removal ofalcohols, of water, and of salts and high-boiling materials.
 6. Themethod for producing 1,3-butylene glycol as claimed in claim 3, whereinthe base is sodium hydroxide, potassium hydroxide, or a mixture thereof.7. 1,3-Butylene glycol having a UV absorbance of less than 0.793 at 210nm when analyzed at any time up to three months after production.
 8. The1,3-butylene glycol according to claim 7, wherein the UV absorbance isless than or equal to 0.002 at 210 nm.